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991.
L. Sun W. X. Zhang J. Ma Y. L. Gao N. Xu C. Y. Pan T. Q. Lu X. Y. Hu F. Jin 《Russian Journal of Coordination Chemistry》2017,43(4):252-259
By self-assembly of delocalized organic ligands (L1 and L2) with Cd(SCN)2, ZnI2 and Zn(NCS)2, three luminescent complexes ZnI2(L1)2 (I), [Cd(L1)2(μ1,3-SCN)2] n (II) and Zn(NCS)2(L2)2 (III) were obtained (L1 = 2-{5,5-dimethyl-3-[2-(pyridine-4-yl)ethenyl]cyclohex-2-enylidene}propanedinitrile and L2 = 2-{5,5-dimethyl-3-[2-(pyridine-3-yl)ethenyl]cyclohex-2-enylidene}propanedinitrile). The structures of the complexes were determined by single crystal X-ray diffraction analysis (CIF files CCDC nos. 1406116 (I), 1406115 (II), and 1400360 (III)). In complex I, Zn(II) is coordinated by two functional organic ligands and two I– ions, to form a I2N2 distorted tetrahedral geometry. In 1D coordination polymer II, the Cd(II) centers show six-coordinated geometries, two organic ligands and four SCN– ions involve in coordination with each Cd(II) center. The thiocyanate groups show μ1,3-SCN bridging coordination modes and the adjacent Cd(II) ions are bridged by double μ1,3-SCN ions to form an infinite chain. In complex III, Zn(II) is coordinated by two functional organic ligands and two NCS– groups, to form a N4 distorted tetrahedral geometry. Compared with the free ligands, the complexes show superior luminescent property with red-shift and enhancement of fluorescence intensity. 相似文献
992.
Frontispiece: New Insight into the Hydrocarbon‐Pool Chemistry of the Methanol‐to‐Olefins Conversion over Zeolite H‐ZSM‐5 from GC‐MS,Solid‐State NMR Spectroscopy,and DFT Calculations 下载免费PDF全文
993.
Laha S Gupta P Simien CE Gao H Castro J Pohl T Killian TC 《Physical review letters》2007,99(15):155001
We study the expansion of ultracold neutral plasmas in the regime in which inelastic collisions are negligible. The plasma expands due to the thermal pressure of the electrons, and for an initial spherically symmetric Gaussian density profile, the expansion is self-similar. Measurements of the plasma size and ion kinetic energy using fluorescence imaging and spectroscopy show that the expansion follows an analytic solution of the Vlasov equations for an adiabatically expanding plasma. 相似文献
994.
W. Gao M. Li R. Klie E.I. Altman 《Journal of Electron Spectroscopy and Related Phenomena》2006,150(2-3):136-149
Oxide catalysts are frequently used to convert toxic species to environmentally benign molecules, and to prevent the formation of toxic species in the first place. In this paper, growth and characterization of model oxide systems employed in both approaches is discussed. An example of the former approach is the selective catalytic reduction (SCR) of NO emitted from power plants by NH3, which employs tungsten and vanadium oxides supported on the anatase polymorph of TiO2. To model SCR catalysts, epitaxial titanium, vanadium and tungsten oxide films were grown using molecular beam epitaxy and magnetron sputtering. Two different anatase orientations were grown on LaAlO3 substrates and their interactions with vanadia were characterized. On LaAlO3 (0 0 1), anatase exposed a (4 × 1) reconstructed (0 0 1) surface. Vanadia lifted the reconstruction and at 1 ML a (1 × 1) surface with mostly V5+ was observed. Continued V2O5 growth led to loss of order, but at high temperatures epitaxial VO2 could be grown; vanadia behaved similarly on anatase films on LaAlO3 (1 1 0). Results suggested that the monolayer is pseudomorphic with O adsorption oxidizing the surface V to 5+, since the anatase structure cannot accommodate more bulk oxygen, only a monolayer can be pseudomorphic and have only V5+. Thus the vanadia monolayer has unique structural and chemical properties that can help explain why vanadia monolayers on TiO2 are much more active than bulk V2O5. For WO3, a series of added row reconstructions were observed as the epitaxial films were reduced. The effect of these structures on surface chemistry was characterized by studying 1-propanol adsorption. The results indicated that the structure of the WO3 surface did not alter its catalytic function but had a strong effect on reaction kinetics. As an example of a system where catalysts prevent the formation of toxic species, the reactivity of oxidized Pd surfaces used in CH4 catalytic combustion were studied. An ordered PdO-like monolayer was found to be less reactive towards CO than adsorbed O on Pd. On the other hand, the PdO layer favored a lower activation energy C3H6 oxidation pathway. The results indicated that Pd oxidation reduces the sticking coefficient of reactive species but once molecules adsorb, the oxide surface can reduce the activation energy for subsequent reaction. 相似文献
995.
Qian Gao Fenghua Chen Jilin Zhang Jiazuan Ni 《Journal of magnetism and magnetic materials》2009,321(8):1052-1057
The surface structure of the iron oxide nanoparticles obtained by the co-precipitation method has been investigated, and a thin layer of α-FeOOH absorbed on surface of the nanoparticle is confirmed by analyses of Fourier transform infrared (FTIR), X-ray photoelectron spectra (XPS) and surface photovoltage spectroscopy (SPS). After annealed at 400 °C, the α-FeOOH can be converted to γ-Fe2O3. The simple-annealed procedure resulted in the formation of Fe3O4@γ-Fe2O3 core/shell structure with improved stability and a higher magnetic saturation value, and also the simple method can be used to obtain core/shell structure in other similar system. 相似文献
996.
IntroductionInengineering,thenonlinearityofshellstructureissometimesobvious.Itisverydifficulttosolvetheproblemofthenonlinearrandomvibration .Inthispaper,wetrytosolveitinthefrequencydomainbyanimprovedstatisticlinearizationmethod .Weconsideronlythegeometr… 相似文献
997.
利用铝+氮或钛+氮离子束辅助沉积改善纯铁摩擦学性能的研究 总被引:1,自引:0,他引:1
离子束辅助沉积是近几年发展起来的一种将离子注入与薄膜沉积融为一体的材料表面改性新技术。利用Al+N+或Ti+N+离子束辅助沉积对工业纯铁进行了表面改性处理,并且就其摩擦学性能与未经表面改性处理之纯铁试样的作了对比试验研究,同时还利用俄歇电子能谱仪、掠角X射线衍射仪和扫描电子显微镜等分析测试手段对离子束改性层的成分深度分布和微观组织结构,以及磨痕的表面形貌和元素面分布进行了分析。结果表明,Al+N+或Ti+N+离子束辅助沉积可以在纯铁表面形成Fe4N、Fe3Al或Fe2N、Fe2Ti等强化相,因而使材料的表层显微硬度分别提高了21.5%和58.4%,稳态摩擦下的摩擦系数分别降低约80%和83%,平均磨损量分别降低约71%和86%;磨损形式主要由纯铁严重的粘着磨损转化为轻微的氧化磨损。 相似文献
998.
For a non-linear system excited by a stochastic load which is expressed as a time series,a recursive method based on the Z-transform is presented.To identify the obtained response time series,a discrete wavelet transform (DWT) technique is proposed. 相似文献
999.
1000.
Gao B Li H Liu H Zhang L Bai Q Ba X 《Chemical communications (Cambridge, England)》2011,47(13):3894-3896
We prepared dendritic perylene bisimide probes with triblock structures: perylene bisimides fluorescence cores, branched oligo(glutamic acid)s and polyethylene glycol chains. These probes showed good water solubility, low cytotoxicity and strong fluorescence in live cells. 相似文献